Apparatus and method for avoiding fluid bypass in particulate filters

ABSTRACT

A filter contains fluent particulate, such as carbon granules. The filter is divided into a plurality of cell chambers by walls, including an upper wall. The upper wall has a surface that faces, and is closest to, the top surface of the particles. The upper wall surface is oriented so that, as the particles settle, any gap formed between the top surface of the particles and a portion of the upper wall surface will not extend from the upstream to the downstream sides of the filter. Instead, contact is maintained between the top surface of the particles and the upper wall surface during fluid flow through the filter, and therefore any gas flowing through the frame must flow through, and through spaces around, particles. An angle between the upper wall surface and the flow direction of gas striking the filter is greater than about three degrees.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/029,049 filed Jul. 25, 2014. The above prior application is herebyincorporated by reference.

STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT

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THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

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REFERENCE TO AN APPENDIX

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BACKGROUND OF THE INVENTION

The invention relates generally to gas filtration and the removal ofcompounds from gases using particulate matter, and more particularly toa frame or other structure for retaining particulate matter throughwhich the gas is forced to reduce and/or remove compounds from the gaswithout the gas bypassing the particulate through large gaps between theparticulate and the frame.

Filters are commonly produced that contain granular, pelletized, orparticulate media that are designed to remove Volatile Organic Compounds(VOCs), odors or any other air-born contaminants that cannot be removedby mechanical or electrostatic filtration methods. As shown in FIGS. 1and 2, these conventional filters may be made of a corrugated paperproduct frame with pockets or “cells” that contain the filtration mediumparticulate 8. The filter 1 may be made using an injection moldedplastic frame that holds the particulate in multiple cells. Upper wall2, lower wall 3 and lateral walls 4 define each of the cells and thewalls 2-4 retain a quantity of filtration medium particulate 8 betweenupstream and downstream mounted, gas-permeable media 5 and 6 (see FIG.2) that contain the particles of the particulate 8 that are larger thanthe pores in the media. The air, gas or liquid passing through theparticulate follows a path that is perpendicular to the planar majorface of the filter.

The particulate is sometimes referred to herein as “carbon” becausecarbon is the most common material used for this filtration purpose. Airthat has greater contact with the carbon is more desirable becausecarbon removes more odors and VOCs from the airstream in a given timeframe than many other such particles. Granular carbon is commonly usedin such filters to capture odors and VOCs from air as the air is forcedthrough a particulate bed. As described above, conventional granular orpelletized carbon filters employ a carrier system which typicallyincludes multiple sidewall baffles that are aligned substantiallyparallel to the air stream, which is substantially perpendicular to theupstream media 5. The baffles, which are the walls 2-4, distribute thecarbon particulate across the entire volume of the filter and hold thecarbon in place when the filter is placed in various orientations. Thenature of the cells is that the faces of the upper and lower walls 2-3that the particulate seats against and that define the cells 8 aresubstantially perpendicular to the planar face of the filter frames asshown in FIGS. 1 and 2. Stated differently, the angle A of FIG. 2 isconventionally about 90 degrees, and, to the inventor's knowledge, isalways substantially perpendicular, which is between about 87 and about93 degrees even taking manufacturing tolerances into consideration.

The most common orientation for such filters during use is vertical.Because of the force of gravity, within each baffle set, or cell, thecarbon particulate may settle to the bottom of the cell. This leaves anopen space S at the top of each cell where air can pass through withoutcoming into contact with the carbon. The filtration medium is loadedinto the cells of the filters when the main plane of each filter is in ahorizontal orientation, but when the filters are in use they are in asubstantially vertical orientation. The geometric nature of the cellsallows the carbon to settle and create a visible void where substantialamounts of air can move through the filter without being forced to gothrough the carbon. This condition is called “bypass” within thefiltration industry and is illustrated in FIG. 2 as the line “B”. Theproblem with bypass is that a substantial amount of gas can pass throughthe open space S of the filter without being affected by the carbonparticles. This produces poor odor and VOC reduction results. Therefore,the need exists for a superior filter frame to reduce or prevent suchbypass.

BRIEF SUMMARY OF THE INVENTION

A filter apparatus is disclosed that contains one or more of any of thefluent particulate described herein, such as carbon granules. Fluentmaterials flow, which can result in settling of the particles into anoverall volume that is slightly smaller than the original volume,resulting in the top surface of the particles settling downwardly. Thefilter is divided into a plurality of cell chambers by walls, includingat least an upper wall. The upper wall has a surface that faces, and isclosest to, the top surface of the particles. The upper wall surface isoriented so that, as the particles settle, any gap formed between thetop surface of the particles and a portion of the upper wall surfacewill not extend from the upstream to the downstream sides of the filterframe. Contact is maintained between the top surface of the particlesand at least a portion of the upper wall surface during fluid flowthrough the filter, and therefore any gas flowing through the frame mustflow through, and through spaces around, particles.

In one embodiment of the invention, the upper wall surface isstrategically oriented relative to the upstream face of the frame whenthe frame is in a vertical orientation, such as when gas flows throughthe frame substantially perpendicular to the upstream face. The upperwall surface is preferably oriented at least greater than about 93degrees relative to the upstream face. It is also contemplated tostrategically orient the upper wall surface relative to vertical,represented by an imaginary vertical line that is perpendicular to gasflow against the upstream face of the filter. In this configuration, theupper wall surface is preferably oriented at least greater than about 93degrees relative to vertical.

It is also contemplated to strategically orient the upper wall surfacerelative to the direction of gas flow striking the upstream face of thefilter. In this configuration, the upper wall surface is oriented atleast greater than about 3 degrees relative to the direction of gasflow. In all cases, the orientation and shape of the upper wall surfaceis such that any settling of the fluent particulate matter does notcause a gap to open that forms a complete path from the upstream to thedownstream faces of the particulate that avoids contact with theparticulate. Thus, all gas flowing through the filter must contact atleast some of the particles.

Each cell is filled with carbon particulate or any other particulatethat the fluid to be filtered desirably makes contact with. At somepoint prior to use, such as during manufacture, the filter is orientedin a horizontal or other non-vertical orientation. When the filter ismoved to a vertical position for use, the shape and angled upper wallsof the cells prevent the carbon from settling and creating an open spacewhere gas that passes through the filter (in a path that beginssubstantially perpendicular to the major surface of the filter) can movethrough the filter without being forced through the particulatematerial.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a front cutaway view illustrating a prior art filter frame.

FIG. 2 is a side view in section illustrating the prior art filter framethrough the line 2-2 of FIG. 1.

FIG. 3 is a front cutaway view illustrating an embodiment of the presentinvention.

FIG. 4 is a side view in section illustrating the embodiment of FIG. 1through the line 4-4 of FIG. 3.

FIG. 5 is view in perspective illustrating an embodiment of the presentinvention.

FIG. 6 is a front view illustrating the embodiment of FIG. 5.

FIG. 7 is a side view in section illustrating the embodiment of FIG. 6through the line B-B.

FIG. 8 is a side view in section illustrating the embodiment of FIG. 6through the line C-C.

In describing the preferred embodiment of the invention which isillustrated in the drawings, specific terminology will be resorted tofor the sake of clarity. However, it is not intended that the inventionbe limited to the specific term so selected and it is to be understoodthat each specific term includes all technical equivalents which operatein a similar manner to accomplish a similar purpose. For example, theword connected or terms similar thereto are often used. They are notlimited to direct connection, but include connection through otherelements where such connection is recognized as being equivalent bythose skilled in the art.

DETAILED DESCRIPTION OF THE INVENTION

U.S. Patent application Ser. No. Application No. 62/029,049 filed Jul.25, 2014 is incorporated in this application by reference.

A filter 10 is made in accordance with the present invention, and has aplurality of baffles or cells formed in the frame 14. The frame may bemade of any rigid material, such as paper, plastic or any other suitablefiltration frame material. The frame may be about one-half to about twoinches thick and can be made to any common width and height, such astwenty inches high by twenty inches wide. A person of ordinary skillwill understand that virtually any thickness, height and widthcombination can be manufactured and used.

Each of the cells is a chamber that contains a quantity of particulatematter 80 and is defined by walls, such as the walls above, below and onboth sides of each cell, and gas-permeable media on the upstream anddownstream sides. The frame walls are preferably gas and particulateimpermeable, but the media on the upstream and downstream sides aregas-permeable to permit gas to flow therethrough with little to norestriction. The gas also flows through the particles themselves, orthrough the gaps formed around the particles where contact is made withother particles, or both. The particulate 80 contained in each cellcannot pass through the openings in the upstream and downstream sides ofthe filter due to the greater size of the particles than the mediaopenings.

An example cell 12 has an upper wall 20, a bottom wall 30 and lateralsidewalls 40. The cell 12 has an upstream media layer 50 and downstreammedia layer 60 mounted to the upstream and downstream surfaces of theframe 14, respectively. As noted above, the layers 50 and 60 aregas-permeable but are not permeable by the particulate 80 in the size inwhich the particulate 80 is used. Therefore, no particulate is lostduring use of the filter 10, in which the filter 10 is orientedsubstantially vertically (as shown in FIG. 4) in a passage, such as anHVAC duct, with sidewalls spaced about the same distance as theperipheral edges of the filter 10, and a gas is forced into the filter10 in a direction along a line perpendicular to the media layer 50.Because of the construction of the walls 20, 30 and 40, along with themedia layers 50 and 60, substantially all particulate 80 remains in thecell 12 during use of the filter 10.

As shown in FIG. 4, at least the upper wall 20 in each of the cells isformed having a surface 20 s (with comparable surfaces in lower cells,such as the surface 30 s) that is substantially non-parallel to the gasstream direction, which is non-perpendicular to the media layer 50. Thelower wall 30 can have a similar orientation to the wall 20, but thelateral walls 40 are preferably substantially perpendicular to the medialayer 50, or parallel to the gas stream direction. It is preferred thatthe surface 20 s is oriented at least over three degrees greater thanparallel to the direction of gas flow. This orientation may be at leastover three degrees greater than perpendicular to the upstream medialayer 50, which media layer 50 is substantially parallel to the upstreammajor surface of the frame 14 to which the media layer 50 is mounted.Thus, the upper wall surface 20 s is at least about greater than 93degrees relative to the media layer 50, as shown in FIG. 4 by thereference numeral N, and relative to any vertical line, such as the lineV of FIG. 4 when the filter is vertically oriented as in FIG. 4.

Because the surface 20 s is angled as described, even if the particulatematter 80 settles (downwardly in the illustration of FIG. 4), thesubstantially horizontal top surface 80 s of the particulate in the cell12 still contacts the upper wall surface 20 s, at least at the portionof the surface 20 s near the downstream media layer 60. This contactprevents the formation of a path for gas to flow through the filter 10without contacting at least some of the particulate 80, which couldoccur if the top surface 80 s settled below the rear surface 20 b of theupper wall 20. But the structure herein prevents settling below 20 b.

The upper wall surface 20 s faces the top surface 80 s of theparticulate 80 in the cell 12, and contacts at least a portion of thetop surface 80 s, even after settling away from the surface 20 s by thefluent particulate 80. Thus, as the surface 20 s guides the gas thatstrikes the media layer 50 perpendicularly and then slightly offset fromperpendicular, as shown schematically by the term “Flow” and are-directed arrow in the lowest cell of FIG. 4, the gas flows through atleast the portion of the thickness of the particulate 80 that contactsthe downstream portion of the surface 20 s. Because the air (or anyother gas) stream direction is preferably perpendicular to the upstreammedia layer 50 when the air strikes the media layer 50, the orientationof the surface 20 s re-directs the air slightly through the particulate80 so that, even if the particulate 80 settles to form a gap, the gasflows through at least some particulate. This re-direction of the gasdoes not cause a substantial increase in pressure drop across the filter10, at least in part because there is little resistance to the airpassing through the gap in the first portion of the space created bysettling, but also because the angle of the surface 20 s, and all othersimilar surfaces, are not extreme enough to cause a large pressure drop.

In the embodiment of FIG. 4, the airstream direction upon striking theupstream media layer 50 is preferably substantially perpendicular to theupstream media layer 50 as shown. When the filter 10 is placed in avertical orientation, whether for storage, transport or use, and theparticulate settles downwardly due to the force of gravity and possiblyvibration, the angled upper cell walls of the filter 10 prevent thecarbon in the cells from creating openings that allow bypass as in theprior art. Thus, all air or other gas that flows through the filter hasa much greater likelihood of coming into contact with the carbon.

The filter 10 has multiple cells, each of which contains carbon or anyother particulate that air, gas or liquid desirably contacts whilepassing through the filter. The person of ordinary skill will understandthat all cells in a filter can be substantially identical, as shown inthe filter 10, or they can be modified to be larger or smaller thanother cells in the same filter. Alternatively, the angles of the upperwall surfaces can be the same or different from cell to cell, eventhough the angles of the upper wall surfaces of all cells in the filter10 are shown to be the same, which is preferred.

The upper walls of the cells are substantially offset from perpendicularto the major surface of the filter that is facing the flow of gas. Thismeans that the upper walls of the cells are substantially non-parallelto the flow direction of air, gas or liquid striking the filter 10. Theangle N between the upper wall surface 20 s and the major face of thefilter 10 is greater than 93 degrees, such as 94, 95, 96 or 100 degreesor more. In an alternative embodiment (not shown), the angle between anupper wall surface and the major face of the filter is less than 87degrees. The offset from parallel to the air flow, or perpendicular tothe major face of the filter, can be as little as a few degrees,depending on the filter thickness, and is preferably 4, 5, 6, 7, 8, 9 or10 degrees or greater. Regardless of the exact angle, the person ofordinary skill will understand that the angle is sufficient to ensurethat preferably at least 90%, more preferably at least 95%, still morepreferably at least 97%, and most preferably about 100% of the fluidpassing through the filter contacts particulate medium in the filter.

There are no limits to the shape of each cell. Examples include, round,square, triangular, curved, trapezoid, irregular, or any shape that canbe conceived that will act as a cell used to hold carbon or any otherdesirable particulate. The size and depth of the filter containing thecells is also not limited; the length, width, and depth dimensions arenot limited to any specific size range. The material of the filter frameis also not limited, and may be plastic, paper, metal, carbon, or anyother suitable material.

Another example of a frame from which a filter made according to theinvention may be made is the frame 114 shown in FIGS. 5-8. The frame 114has a plurality of cells defined, in part, by the substantially curvedwalls 120 and 130. The walls 120 and 130 provide the upper boundariesfor two of the cells, which extend laterally from one side of the frame114 to the opposite side of the frame. Because the members 140 extend tothe upstream face of the frame 114, and to the downstream face, but donot completely separate the cells, the members 140 do not form lateralboundaries to cells, and are to support the media layers at the upstreamand downstream sides. The only sidewalls that retain particulate fromlateral flow are the peripheral frame members 114 a and 114 b. Thus,particulate in the frame 114 is retained in cells defined by thehorizontally-oriented pairs of vertically-spaced members, such asbetween the walls 120 and 130, and between the peripheral frame members114 a and 114 b.

As can be seen in FIG. 6, the walls 120 and 130 form angled surfaces atthe tops of each chamber below them, thereby forming an angled surfacerelative to the particulate (not shown) that would be placed beneatheach member. Thus, the angled surfaces of the walls 120 and 130 providethe benefits described above with the filter 10.

A filter made according to the invention thus contains a granular orpelletized medium that is designed to remove VOCs, odors and/or any gasor air-born contaminants. Typically such contaminants are not removed bymechanical or electrostatic filtration methods. The upper cell walls ofthe filter are more or less than substantially perpendicular to themajor, planar surface of the filter, thus leaving the upper cell wallsnon-parallel to the path of fluid flow striking the filter. The shape ofthe cell and the angle of the cell's upper wall are such that when thefiltration medium is loaded into the filter and then oriented in avertical position, the natural settling of the particulate does notcreate a void through which a substantial amount of air can pass withoutbeing forced through the carbon or other particulate bed. Instead, theshape of the cell and the angle of the upper cell walls create acondition in which substantially all gas or air that moves through thefilter is forced into contact with the filtration medium containedwithin the filter.

This detailed description in connection with the drawings is intendedprincipally as a description of the presently preferred embodiments ofthe invention, and is not intended to represent the only form in whichthe present invention may be constructed or utilized. The descriptionsets forth the designs, functions, means, and methods of implementingthe invention in connection with the illustrated embodiments. It is tobe understood, however, that the same or equivalent functions andfeatures may be accomplished by different embodiments that are alsointended to be encompassed within the spirit and scope of the inventionand that various modifications may be adopted without departing from theinvention or scope of the following claims.

The invention claimed is:
 1. A filtration apparatus containing fluentparticles that chemically modify compounds in gases that make contactwith the particles, the apparatus comprising: (a) a frame divided into aplurality of cell chambers, each cell chamber containing a quantity ofthe particles, each cell chamber defined by at least an upper wall thatis positioned above a top surface of the respective quantity of theparticles when the frame is oriented substantially vertically inoperable orientation, the upper wall having an upper wall surface thatfaces, and contacts, at least a portion of the top surface of therespective quantity of particles; and (b) the upper wall surface formsan angle with an upstream face of the frame that is greater than about93 degrees, and the upstream face of the frame contacts the respectivequantity of the particles, thereby forcing all gas flowing through theframe to flow in contact with at least some of the particles.
 2. Thefiltration apparatus in accordance with claim 1, wherein each cellchamber is further defined by a lower wall that is positioned below thequantity of the particles when the frame is oriented substantiallyvertically in operable orientation and lateral walls positioned onopposite sides of the quantity of the particles, and at least thelateral walls have surfaces that are substantially perpendicular to theupstream face of the frame.
 3. The filtration apparatus in accordancewith claim 2, wherein a first fluid-permeable media layer that isimpermeable to the fluent particles is mounted on the upstream side ofthe frame to retain the particles in each cell chamber, and a secondfluid-permeable media layer that is impermeable to the fluent particlesis mounted on the downstream side of the frame to retain the particlesin each cell chamber.
 4. A filtration apparatus containing fluentparticles that chemically modify compounds in gases that make contactwith the particles, the apparatus comprising: (a) a frame divided into aplurality of cell chambers, each cell chamber containing a quantity ofthe particles, each cell chamber defined by at least an upper wall thatis positioned above a top surface of the respective quantity of theparticles when the frame is oriented substantially vertically, the upperwall having an upper wall surface that faces, and contacts, at least aportion of the top surface of the respective quantity of particles; and(b) the upper wall surface forms an angle with gas flowing through theframe that is greater than about 3 degrees, and the upstream face of theframe contacts the respective quantity of the particles, thereby forcingall gas flowing through the frame to flow in contact with at least someof the particles.
 5. The filtration apparatus in accordance with claim4, wherein each cell chamber is further defined by a lower wall that ispositioned below the quantity of the particles when the frame isoriented substantially vertically in operable orientation and lateralwalls positioned on opposite sides of the quantity of the particles, andat least the lateral walls have surfaces that are substantiallyperpendicular to the upstream face of the frame.
 6. The filtrationapparatus in accordance with claim 5, wherein a first fluid-permeablemedia layer that is impermeable to the fluent particles is mounted onthe upstream side of the frame to retain the particles in each cellchamber, and a second fluid-permeable media layer that is impermeable tothe fluent particles is mounted on the downstream side of the frame toretain the particles in each cell chamber.
 7. A filtration apparatuscontaining fluent particles that chemically modify compounds in gasesthat make contact with the particles, the apparatus comprising: (a) avertical frame divided into a plurality of cell chambers, each cellchamber containing a quantity of the particles, each cell chamberdefined by at least an upper wall that is positioned above a top surfaceof the respective quantity of the particles, the upper wall having anupper wall surface that faces, and contacts, at least a portion of thetop surface of the respective quantity of particles; and (b) the upperwall surface forms an angle with vertical that is greater than about 93degrees, thereby forcing all gas flowing through the frame to flow incontact with at least some of the particles.
 8. The filtration apparatusin accordance with claim 7, wherein each cell chamber is further definedby a lower wall that is positioned below the quantity of the particleswhen the frame is oriented substantially vertically in operableorientation and lateral walls positioned on opposite sides of thequantity of the particles, and at least the lateral walls have surfacesthat are substantially perpendicular to the upstream face of the frame.9. The filtration apparatus in accordance with claim 8, wherein a firstfluid-permeable media layer that is impermeable to the fluent particlesis mounted on the upstream side of the frame to retain the particles ineach cell chamber, and a second fluid-permeable media layer that isimpermeable to the fluent particles is mounted on the downstream side ofthe frame to retain the particles in each cell chamber.
 10. A filtrationapparatus containing fluent particles that chemically modify compoundsin gases that make contact with the particles, the apparatus comprising:(a) a substantially vertical frame divided into a plurality of cellchambers, each cell chamber containing a quantity of the particles, eachcell chamber defined by at least an upper wall that is spaced from a topsurface of the quantity of particles, the upper wall having an upperwall surface that faces, and contacts at least a portion of the topsurface of the respective quantity of particles; and (b) the upper wallsurface has a shape and orientation that, if the quantity of particlessettles to space the respective top surface of the quantity of particlesaway from a first portion of the upper wall surface, at least a secondportion of the upper wall surface maintains contact with the respectivetop surface of the quantity of particles, thereby forcing all gasflowing through the frame to flow in contact with at least some of theparticles, wherein the upper wall surface is oriented relative to theflow of gas striking the frame by at least three degrees.
 11. Thefiltration apparatus in accordance with claim 10, wherein each cellchamber is further defined by a lower wall that is positioned below thequantity of the particles when the frame is oriented substantiallyvertically in operable orientation and lateral walls positioned onopposite sides of the quantity of the particles, and at least thelateral walls have surfaces that are substantially perpendicular to theupstream face of the frame.
 12. The filtration apparatus in accordancewith claim 11, wherein a first fluid-permeable media layer that isimpermeable to the fluent particles is mounted on the upstream side ofthe frame to retain the particles in each cell chamber, and a secondfluid-permeable media layer that is impermeable to the fluent particlesis mounted on the downstream side of the frame to retain the particlesin each cell chamber.